A. Field of the Invention
This invention relates to the smooth-scrolling or scrolling by one pixel at a time of a display screen comprising a plurality of display lines, and more particularly the invention relates to performing the smooth-scrolling for each display line.
B. Description of Related Art
As disclosed in Japanese Patent Laid-open Nos. 160984/83, 182690/83, 182691/83 and Japan Patent Publication No. 36779/83, the scrolling of a displayed image on a display screen has been principally attained by shift-controlling the pixels of the image of an entire display screen or by shift controlling the pixels of a representative character or a display block. However, these conventional scrolling techniques of the prior art have not been able to smooth scroll line by line of the displayed image independently, selectively and dynamically.
It is therefore an object of the present invention to provide a method and apparatus for performing selective and dynamic smooth scrolling of a displayed image line by line.